US11604014B2 - Electric motor and compressor having the same - Google Patents

Electric motor and compressor having the same Download PDF

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Publication number
US11604014B2
US11604014B2 US17/060,705 US202017060705A US11604014B2 US 11604014 B2 US11604014 B2 US 11604014B2 US 202017060705 A US202017060705 A US 202017060705A US 11604014 B2 US11604014 B2 US 11604014B2
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Prior art keywords
slot
permanent magnet
rotor
axis
core
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US17/060,705
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US20210222922A1 (en
Inventor
Injae Lee
Sangjoon EUM
JeongHwan KIM
Mingyu Kim
Heedon Jung
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LG Electronics Inc
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LG Electronics Inc
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Assigned to LG ELECTRONICS INC. reassignment LG ELECTRONICS INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: EUM, Sangjoon, Jung, Heedon, KIM, MINGYU, LEE, INJAE
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B31/00—Compressor arrangements
    • F25B31/02—Compressor arrangements of motor-compressor units
    • F25B31/026—Compressor arrangements of motor-compressor units with compressor of rotary type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C23/00—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids
    • F04C23/02—Pumps characterised by combination with, or adaptation to, specific driving engines or motors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
    • F04C29/0042—Driving elements, brakes, couplings, transmissions specially adapted for pumps
    • F04C29/0085—Prime movers
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/26—Rotor cores with slots for windings
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/27—Rotor cores with permanent magnets
    • H02K1/2706—Inner rotors
    • H02K1/272—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
    • H02K1/274—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets
    • H02K1/2753—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets the rotor consisting of magnets or groups of magnets arranged with alternating polarity
    • H02K1/276—Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM]
    • H02K1/2766—Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM] having a flux concentration effect
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/28—Means for mounting or fastening rotating magnetic parts on to, or to, the rotor structures
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K21/00—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
    • H02K21/12—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets
    • H02K21/14—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets rotating within the armatures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2210/00—Fluid
    • F04C2210/26—Refrigerants with particular properties, e.g. HFC-134a
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2240/00—Components
    • F04C2240/40—Electric motor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/07—Details of compressors or related parts

Definitions

  • the present disclosure relates to an electric motor, and a compressor having the same.
  • Electric motors are also classified into a direct-current (DC) motor and an alternating-current (AC) motor according to power used, and the AC motor is widely used because of its simple structure, small size, and light weight.
  • DC direct-current
  • AC alternating-current
  • the AC motor is classified into a single-phase alternating current type and a three-phase alternating current type, and also classified into an induction motor, a synchronous motor, and a commutator motor according to a type of a rotor.
  • the rotor is provided with permanent magnets.
  • the permanent magnet is coupled to an outer circumferential surface of the rotor or is inserted into the rotor in an axial direction.
  • some related art electric motors are provided with a plurality of slits (holes) formed through a portion of the core outside the permanent magnets of the rotor core so as to reduce vibration and noise during operation.
  • the slits are formed symmetrically with respect to a d-axis (i.e., a line connecting a center of a magnetic pole (N pole, S pole) and a center of the rotor).
  • a d-axis i.e., a line connecting a center of a magnetic pole (N pole, S pole) and a center of the rotor.
  • the inertia of the rotor decreases, thereby increasing vibration and noise during low speed rotation.
  • the structure of the related art electric motors in which the plurality of slits is formed on both sides with respect to the d-axis, also causes an increase in pressure (current) during the low speed rotation, thereby decreasing operation efficiency.
  • Another aspect of the present disclosure is to provide an electric motor capable of suppressing an increase in pressure during low speed rotation and improving operation efficiency, and a compressor having the same.
  • Another aspect of the present disclosure is to provide an electric motor capable of decreasing vibration and noise caused by an MPF of a rotor rotating in one direction and improving operation efficiency, and a compressor having the same.
  • the electric motor may include a stator, and a rotor disposed in the stator with a preset air gap from the stator to be rotatable in one direction.
  • the rotor may include a rotation shaft, a rotor core coupled to the rotation shaft, and a plurality of permanent magnets coupled to the rotor core in an axial direction and arranged to form different magnetic poles along a circumferential direction.
  • each of the plurality of permanent magnet insertion portions may include a first permanent magnet insertion portion into which the first permanent magnet is inserted, and a second permanent magnet insertion portion into which the second permanent magnet is inserted.
  • the at least one slot may be provided with a first side arranged in parallel at an outside of an outer side of the first permanent magnet insertion portion, and a second side extending from the first side to be in parallel with the outer side of the second permanent magnet insertion portion.
  • the third side may have a length shorter than a length of the first side
  • the fourth side may have a length shorter than a length of the second side.
  • the at least one slot may further be provided with a fifth side extending from the third side to be in parallel with the second side, and a sixth side extending from the fourth side to be in parallel with the first side and connected to the fifth side.
  • the slot may be provided with a third side extending from an end portion of the second side to be in parallel with the first side, and a connection section connecting the first side and the third side.
  • the first permanent magnet insertion portion may be provided with a first flux barrier extending along a lengthwise direction of the first permanent magnet.
  • the second permanent magnet insertion portion may be provided with a second flux barrier extending along a lengthwise direction of the second permanent magnet.
  • the first permanent magnet insertion portion may be provided with a first expansion slot expanded toward the d-axis.
  • the second permanent magnet insertion portion may be provided with a second expansion slot expanded toward the d-axis.
  • the first expansion slot may have a larger area than an area of the second expansion slot.
  • the first expansion slot may be provided with a first protruding portion protruding toward the d-axis by a preset first height, and a second protruding portion protruding at one side of the first protruding portion by a second height shorter than the first height.
  • the second expansion slot may have a lower protrusion height than the first expansion slot.
  • the front slot and the rear slot may be provided with a first side arranged in parallel with the outer side of the first permanent magnet insertion portion, and a second side extending from the first side to be in parallel with the outer side of the second permanent magnet insertion portion.
  • the rear slot may be provided with a third side extending from an end portion of the second side to be in parallel with the first side, and a fourth side extending from the third side to be in parallel with the first side.
  • the slot may be further provided with a central slot formed over the front portion and the rear portion of the d-axis.
  • the front slot may be provided with a first front slot formed in the front portion of the d-axis, and a second front slot formed in an outer end region of the first permanent magnet.
  • the rear slot may be formed in an outer end region of the second permanent magnet.
  • the outer core part of the first permanent magnet insertion portion and the second permanent magnet insertion portion may be divided into the front portion of the d-axis and the rear portion of the d-axis with respect to the d-axis.
  • the front portion of the d-axis may be divided into a d-axis front outer part and a d-axis front inner part by a division line passing vertically through the d-axis
  • the rear portion of the d-axis may be divided into a d-axis rear inner part and a d-axis rear outer part by the division line passing vertically through the d-axis.
  • the slot may be configured such that a slot area of the d-axis front inner part is equal to or smaller than a slot area of the d-axis front outer part, a slot area of the d-axis rear inner part is equal to or smaller than a slot area of the d-axis front inner part, and a slot area of the d-axis rear outer part is equal to or smaller than a slot area of the d-axis rear inner part.
  • a compressor which may include a case, a compression unit provided inside the case to compress a refrigerant, and the electric motor provided inside the case to apply driving force to the compression unit.
  • the compression unit may include a cylinder having an inner accommodation space, and a roller rotatably disposed in the cylinder and connected to the rotation shaft of the electric motor.
  • a slot can be formed through a rotor in an axial direction in a manner that a core area of a front portion of a d-axis is smaller than a core area of a rear portion of the d-axis in a rotating direction of the rotor, which may result in suppressing an occurrence of vibration and noise due to MPF and a decrease in inertia of the rotor due to the formation of the slot.
  • a slot formed in a front region of the d-axis and a slot formed in a rear region of the d-axis in a rotating direction of the rotor may be asymmetrical with each other, which may result in remarkably suppressing an occurrence of vibration and noise due to MPF of an electric motor appropriate for a uni-directional rotation.
  • FIG. 1 is a sectional view of a compressor having an electric motor in accordance with one implementation.
  • FIG. 2 is an enlarged view of the electric motor of FIG. 1 .
  • FIG. 3 is a horizontal sectional view of the electric motor of FIG. 2 .
  • FIG. 4 is a main portion enlarged view of the rotor of FIG. 3 .
  • FIG. 5 is an enlarged view of a slot and a permanent magnet insertion portion of FIG. 4 .
  • FIG. 6 is an enlarged view of the slot of FIG. 5 .
  • FIG. 7 is an enlarged view of a first permanent magnet insertion portion of FIG. 5 .
  • FIG. 8 is an enlarged view of a second permanent magnet insertion portion of FIG. 5 .
  • FIG. 9 is a horizontal sectional view of an electric motor in accordance with another implementation.
  • FIG. 10 is an enlarged view of a slot region of FIG. 9 .
  • FIG. 11 is a horizontal sectional view of an electric motor in accordance with another implementation.
  • FIG. 12 is an enlarged view of a slot region of FIG. 11 .
  • FIG. 13 is a horizontal sectional view of an electric motor in accordance with another implementation.
  • FIG. 14 is an enlarged view of a slot region of FIG. 13 .
  • FIG. 15 is a horizontal sectional view of an electric motor in accordance with another implementation.
  • FIG. 16 is an enlarged view of a slot region of FIG. 15 .
  • FIG. 17 is a horizontal sectional view of an electric motor in accordance with another implementation.
  • FIG. 18 is an enlarged view of a slot region of FIG. 17 .
  • FIG. 1 is a sectional view of a compressor having an electric motor in accordance with one implementation.
  • a compressor having an electric motor according to this implementation may include a case 110 , a compression unit 150 , and an electric motor 200 .
  • the case 110 may have an accommodation space formed therein.
  • the case 110 may be configured to form a sealed accommodation space therein.
  • the compression unit 150 may be provided at one side (a lower side in the drawing) inside the case 110 .
  • the compression unit 150 may include a cylinder 160 , and a roller 180 rotatably disposed inside the cylinder 160 .
  • the cylinder 160 may also be provided therein with a vane brought into contact with the roller 180 to perform a relative motion, in addition to the roller 180 rotatably disposed therein.
  • the roller 180 may be connected to a rotation shaft 260 of the electric motor 200 . Accordingly, the roller 180 may rotate inside the cylinder 160 centering on the rotation shaft 260 .
  • the cylinder 160 may be configured to be open on both upper and lower sides thereof in the drawing, for example.
  • An upper bearing 165 may be provided on an upper side of the cylinder 160 .
  • a lower bearing 175 may be provided on a lower side of the cylinder 160 .
  • the upper bearing 165 and the lower bearing 175 may be coupled to block the upper and lower sides of the cylinder 160 , respectively.
  • the upper bearing 165 and the lower bearing 175 may rotatably support the rotation shaft 260 of the electric motor 200 accommodated therein.
  • a discharge port 167 through which a compressed refrigerant is discharged may be formed through the upper bearing 165 .
  • the upper bearing 165 may be provided with a discharge valve 169 for opening and closing the discharge port 167 .
  • a discharge cover 170 may be provided on the upper bearing 165 .
  • a suction pipe 120 through which a refrigerant is introduced may communicate with one side (a right side in the drawing) of the cylinder 160 .
  • the suction pipe 120 may extend externally through the case 110 .
  • a discharge pipe 130 through which a refrigerant is discharged may be provided through an upper side of the case 110 .
  • the discharge pipe 130 may extend upwardly.
  • the suction pipe 120 may communicate with an accumulator 125 .
  • the accumulator 125 may be configured such that a refrigerant filled therein is separated into a gaseous refrigerant and a liquid refrigerant by a specific gravity difference.
  • the electric motor 200 may be provided above the compression unit 150 inside the case 110 .
  • the electric motor 200 may include a stator 210 , and a rotor 250 rotatably disposed in the stator 210 with a preset gap G from the stator 210 .
  • the stator 210 may include, for example, a stator core 220 fitted in the case 110 , and a stator coil 230 wound around the stator core 220 .
  • the rotor 250 may include, for example, a rotation shaft 260 , a rotor core 270 coupled to the rotation shaft 260 , and a plurality of permanent magnets 450 coupled to the rotor core 270 .
  • the electric motor 200 of this implementation may be configured to rotate in one direction (counterclockwise in the drawing) along a circumferential direction of the rotor 250 (the stator 210 ), for example.
  • the rotation shaft 260 may extend to both sides of the rotor core 270 .
  • a lower region of the rotation shaft 260 may be rotatably supported by the upper bearing 165 and the lower bearing 175 .
  • An eccentric portion 262 may be formed at the lower region of the rotation shaft 260 .
  • the eccentric portion 262 may be disposed within the cylinder 160 .
  • the eccentric portion 262 may be coupled with the roller 180 .
  • the roller 180 may rotate (eccentrically move) centering on the rotation shaft 260 inside the cylinder 160 . Accordingly, a refrigerant introduced into the cylinder 160 through the suction pipe 120 may be compressed and then discharged to the outside of the cylinder 160 through the discharge port 167 .
  • FIG. 2 is an enlarged view of the electric motor of FIG. 1
  • FIG. 3 is a horizontal sectional view of the electric motor of FIG. 2
  • a rotor accommodation opening 224 may be formed in the stator core 220 so that the rotor 250 may be rotatably accommodated.
  • the stator core 220 may be formed by stacking a plurality of electrical sheets 222 in an insulating manner.
  • the rotor accommodation opening 224 may be formed through the stator core 220 in the axial direction.
  • the stator core 220 may be provided with a plurality of slots 226 and teeth 228 alternately formed on a circumference of the rotor accommodation opening 224 .
  • the implementation illustrates that the slots 226 and the teeth 228 are each provided by nine in number, but this is merely illustrative. The number may be appropriately adjusted.
  • the stator coil 230 may be configured to be connected in a preset pattern via the slots 226 .
  • the rotor 250 may be provided with a plurality of permanent magnets 450 forming different magnetic poles (N pole and S pole) along the circumferential direction.
  • the rotor 250 may have six poles along the circumferential direction, for example.
  • Three teeth 228 of the stator core 220 may be disposed correspondingly per two poles of the rotor 250 .
  • the permanent magnet 450 may be formed in a shape with a rectangular cross section.
  • the permanent magnet 450 may be coupled to the rotor core 270 along the axial direction.
  • the permanent magnet 450 may be formed thin in a rectangular parallelpiped shape, for example.
  • the rotor core 270 may be formed by stacking a plurality of electrical sheets 272 in an insulating manner.
  • a rotation shaft opening 274 in which the rotation shaft 260 is inserted may be formed through a center of the rotor core 270 .
  • Permanent magnet insertion portions 280 through which the permanent magnets 450 are inserted may be formed through the rotor core 270 in the axial direction.
  • End plates 460 for blocking the permanent magnet insertion portions 280 may be provided on both ends of the rotor core 270 , respectively. This may result in preventing separation of the permanent magnets 450 in the axial direction.
  • the rotor core 270 may be provided with a balance weight 470 that generates an unbalanced force in one direction during rotation.
  • the balance weight 460 may be coupled to an outer side of the end plate 460 . This implementation illustrates the case where the balance weight 470 extends on an upper side of the rotor core 270 .
  • the stator 250 may be provided with two permanent magnets 450 for each pole.
  • the permanent magnet 450 may include a first permanent magnet 451 and a second permanent magnet 452 for each pole.
  • the first permanent magnet 451 and the second permanent magnet 452 may be formed of the same material, for example.
  • the first permanent magnet 451 and the second permanent magnet 452 may have the same size and shape, for example.
  • FIG. 4 is a main portion enlarged view of the rotor of FIG. 3 .
  • the rotor core 270 may include a first permanent magnet insertion portion 290 into which the first permanent magnet 451 is inserted.
  • the rotor core 270 may include a second permanent magnet insertion portion 310 into which the second permanent magnet 452 is inserted.
  • a d-axis d may be disposed between the first permanent magnet insertion portion 290 and the second permanent magnet insertion portion 310 .
  • the d-axis d may be shown as an extension line connecting a center of each magnetic pole of the rotor 250 and a center O of the rotor 250 .
  • a q-axis q may be disposed between the magnetic poles of the rotor 250 . More specifically, the q-axis q may be illustrated as an extension line connecting a point where a portion between the poles of the rotor 250 is divided into two equal parts to the center O of the rotor 250 .
  • the first permanent magnet 451 may be disposed such that an end portion adjacent to the d-axis d faces (is closed to) the center of the rotor core 270 , and another end portion spaced apart from the d-axis d is close to an end portion of the rotor core 270 .
  • the second permanent magnet 452 may be disposed such that an end portion adjacent to the d-axis d faces (is close to) the center of the rotor core 270 , and another end portion spaced apart from the d-axis d is close to the end portion of the rotor core 270 .
  • the first permanent magnet 451 and the second permanent magnet 452 may be arranged in a “V” shape based on the d-axis d.
  • the first permanent magnet 451 and the second permanent magnet 452 may be arranged, for example, to form an interior angle, which corresponds to a preset angle (e.g., 108 degrees).
  • the first permanent magnet insertion portion 290 may be provided with an inner side 292 Si and an outer side 292 So arranged parallel with each other.
  • the second permanent magnet insertion portion 310 may be provided with an inner side 312 Si and an outer side 312 So arranged parallel with each other.
  • the outer side 292 So of the first permanent magnet insertion portion 290 and the outer side 312 So of the second permanent magnet insertion portion 310 may form 108 degrees.
  • the first permanent magnet insertion portion 290 and the second permanent magnet insertion portion 310 may be provided with permanent magnet clearance suppressing portions 330 , respectively, for suppressing clearances of the first permanent magnet 451 and the second permanent magnet 452 .
  • Each permanent magnet clearance suppressing portion 330 may include an inner suppressing portion 330 a and an outer suppressing portion 330 b .
  • the inner suppressing portions 330 a may be brought into contact with inner end portions of the first permanent magnet 451 and the second permanent magnet 452 , respectively, and the outer suppressing portions 330 b may be brought into contact with outer end portions of the first permanent magnet 451 and the second permanent magnet 452 , respectively.
  • the electric motor 200 of this implementation may be configured such that a Magnetic pull force (MPF) acting between the stator core 220 and the rotor core 270 is asymmetrically formed based on the d-axis d.
  • MPF Magnetic pull force
  • the rotor core 270 may include, for example, slots 400 each axially formed therethrough at an outer side (outer part, outer region) of the permanent magnet 450 (i.e., the first permanent magnet 451 and the second permanent magnet 452 ) such that the MPF is asymmetrically formed based on the d-axis d.
  • a core reduction of a rear portion 350 r of the d-axis d with respect to the d-axis d can be suppressed, thereby preventing an occurrence of a decrease in inertia of the rotor core 270 caused due to the formation of the slot 400 .
  • FIG. 5 is an enlarged view of a slot and a permanent magnet insertion portion of FIG. 4
  • FIG. 6 is an enlarged view of the slot of FIG. 5
  • the slot 400 may be formed in a front portion 350 f of the d-axis din a rotating direction of the rotor core 270 .
  • a core area of the front portion 350 f of the d-axis d may become smaller than a core area of the rear portion 350 r of the d-axis d, such that a magnetic flux passing through the rear portion 350 r of the d-axis d can increase more than a magnetic flux passing through the front portion 350 f of the d-axis d.
  • the outer core part 350 of the first permanent magnet insertion portion 290 and the second permanent magnet insertion portion 310 may be divided into the front portion 350 f of the d-axis d and the rear portion 350 r of the d-axis d with respect to the d-axis d.
  • the front portion 350 f of the d-axis d may be divided into a d-axis front outer part ⁇ circle around (1) ⁇ and a d-axis front inner part ⁇ circle around (2) ⁇ by a division line Lp passing vertically through the d-axis d.
  • the rear portion 350 r of the d-axis d may be divided into a d-axis rear inner part ⁇ circle around (3) ⁇ and a d-axis rear outer part ⁇ circle around (4) ⁇ by the division line Lp passing vertically through the d-axis d.
  • the front portion 350 f of the d-axis d and the rear portion 350 r of the d-axis d may be divided, for example, by the d-axis d such that each divided part has the same core area.
  • the d-axis front outer part ⁇ circle around (1) ⁇ and the d-axis front inner part ⁇ circle around (2) ⁇ may be, for example, divided by the division line Lp to have the same core area.
  • the d-axis rear inner part ⁇ circle around (3) ⁇ and the d-axis rear outer part ⁇ circle around (4) ⁇ may be, for example, divided by the division line Lp to have the same core area.
  • the outer core part 350 of the permanent magnet insertion portion 280 may refer to a core part that is defined by the outer side 292 So of the first permanent magnet insertion portion 290 , the outer side 312 So of the second permanent magnet insertion portion 310 , a first extension line Le 1 extending from the outer side 292 So of the first permanent magnet insertion portion 290 up to an outer circumference of the rotor core 270 , and a second extension line Le 2 extending from the outer side 312 So of the second permanent magnet insertion portion 310 up to the outer circumference of the rotor core 270 .
  • the slot 400 may be formed in a manner that the core area of the d-axis front inner part ⁇ circle around (2) ⁇ is equal to or larger than the core area of the d-axis front outer part ⁇ circle around (1) ⁇ , the core area of the d-axis rear inner part ⁇ circle around (3) ⁇ is equal to or larger than the core area of the d-axis front inner part ⁇ circle around (2) ⁇ , and the core area of the d-axis rear outer part ⁇ circle around (4) ⁇ is equal to or larger than the core area of the d-axis rear inner part ⁇ circle around (3) ⁇ .
  • a slot area of the d-axis rear inner part ⁇ circle around (3) ⁇ may be equal to or larger than a slot area of the d-axis rear outer part ⁇ circle around (4) ⁇ .
  • a slot area of the d-axis front inner part ⁇ circle around (2) ⁇ may be equal to or larger than a slot area of the d-axis rear inner part ⁇ circle around (3) ⁇ .
  • a slot area of the d-axis front outer part ⁇ circle around (1) ⁇ may be equal to or larger than a slot area of the d-axis front inner part ⁇ circle around (2) ⁇ .
  • the core area of the front portion 350 f of the d-axis d may become smaller than the core area of the rear portion 350 r of the d-axis d.
  • an area of the slot 400 of the front portion 350 f of the d-axis d may become smaller than the core area of the front portion 350 f of the d-axis d.
  • the slot 400 may be formed in a penetrating manner, for example, to have a shape including a plurality of rectangular sections.
  • the slot 400 may be divided into a plurality of rectangular sections.
  • the plurality of rectangular sections of the slot 400 may be provided with unit plane figures 410 (e.g., rhombuses, parallelograms, rectangles or squares, circles, hexagons, etc.) with a relatively small area (size).
  • unit plane figures 410 e.g., rhombuses, parallelograms, rectangles or squares, circles, hexagons, etc.
  • the slot 400 may be formed, for example, by dividing the outer core part 350 of the permanent magnet insertion portion 280 into the unit plane figures 410 , forming unit slots having sizes corresponding to the unit plane figures 410 in a penetrating manner, analyzing changes in MPF, and connecting outlines of unit slots (the unit plane figures 410 ) exhibiting a great effect of suppressing vibration and noise caused due to the MPF during the formation of the unit slots.
  • Each side of the plurality of rectangular sections of the slot 400 may be configured as, for example, an integer multiple of one side of the unit plane FIG. 410 .
  • the slot 400 may include a first side 400 S 1 arranged at the outside of the outer side 292 So of the first permanent magnet insertion portion 290 to be in parallel with the outer side 292 So, and a second side 400 S 2 extending from the first side 400 S 1 to be in parallel with the outer side 312 So of the second permanent magnet insertion portion 310 .
  • An interior angle between the first side 400 S 1 and the second side 400 S 2 of the slot 400 may be equal to an interior angle (e.g., 108 degrees) formed between the outer side 292 So of the first permanent magnet insertion portion 290 and the outer side 312 So of the second permanent magnet insertion portion 310 .
  • the interior angle between the first side 400 S 1 and the second side 400 S 2 of the slot 400 may be, for example, 108 degrees.
  • the slot 400 may include a third side 400 S 3 disposed outside the first side 400 S 1 in parallel, and a fourth side 400 S 4 disposed at the outside of the second side 400 S 2 in parallel.
  • first side 400 S 1 and the third side 400 S 3 may be connected linearly (i.e., by a straight line 400 S 7 ).
  • second side 400 S 2 and the fourth side 400 S 4 may be connected linearly (e.g., by a straight line 400 S 8 ).
  • the third side 400 S 3 and the fourth side 400 S 4 of the slot 400 may form an interior angle of 108 degrees.
  • the third side 400 S 3 may have a length shorter than the first side 400 S 1 .
  • the fourth side 400 S 4 may have a length shorter than the second side 400 S 2 .
  • the slot 400 may further include a fifth side 400 S 5 extending from the third side 400 S 3 to be in parallel with the second side 400 S 2 , and a sixth side 400 S 6 extending from the fourth side 400 S 4 to be in parallel with the firth side 400 S 1 and connected to the fifth side 400 S 5 .
  • the third side 400 S 4 and the fifth side 400 S 5 may form an interior angle of 108 degrees.
  • the fourth side 400 S 4 and the sixth side 400 S 6 may form an interior angle of 108 degrees.
  • the slot 400 may include, for example, a first rectangular section ⁇ circle around (a) ⁇ , a second rectangular section ⁇ circle around (b) ⁇ , and a third rectangular section ⁇ circle around (c) ⁇ .
  • the first rectangular section ⁇ circle around (a) ⁇ , the second rectangular section ⁇ circle around (b) ⁇ , and the third rectangular section ⁇ circle around (c) ⁇ may be configured to have different numbers of unit plane figures 410 .
  • FIG. 410 may be implemented as a parallelogram having two sides parallel with the first side 400 S 1 of the slot 400 and two other sides parallel with the second side 400 S 2 of the slot 400 .
  • the outline of the slot 400 may be elaborate and various in shape.
  • Corners of each rectangular section of the slot 400 may be configured to have a minimum radius of curvature r for manufacturing (molding), for example.
  • first permanent magnet insertion portion 290 and the second permanent magnet insertion portion 310 may be asymmetrical with each other based on the d-axis d.
  • the first permanent magnet insertion portion 290 and the second permanent magnet insertion portion 310 may have different areas from each other.
  • the area of the first permanent magnet insertion portion 290 may be larger than the area of the second permanent magnet insertion portion 310 .
  • the first permanent magnet insertion portion 290 may include, for example, a first expansion slot 295 expanded toward the d-axis d.
  • the second permanent magnet insertion portion 310 may include, for example, a second expansion slot 315 expanded toward the d-axis d.
  • an area of the first expansion slot 295 may be larger than an area of the second expansion slot 315 .
  • FIG. 7 is an enlarged view of the first permanent magnet insertion portion of FIG. 5
  • FIG. 8 is an enlarged view of the second permanent magnet insertion portion of FIG. 5
  • the first permanent magnet insertion portion 290 may include a first permanent magnet accommodation space 292 in which the first permanent magnet 451 is accommodated, a first flux barrier 294 extending from one side of the first permanent magnet accommodation space 292 , and the first expansion slot 295 expanded toward the d-axis d.
  • the first expansion slot 295 may include rectangular sections 297 having different sizes.
  • the rectangular section 297 of the first expansion slot 295 may include, for example, a first protruding portion 297 a protruding toward the d-axis d by a predetermined first height H 1 , and a second protruding portion 297 b protruding at one side of the first protruding portion 297 a by a second height H 2 lower than the first height H 1 .
  • the rectangular section 297 (i.e., the first protruding portion 297 a and the second protruding portion 297 b ) may include, for example, a plurality of unit plane figures 410 having a relatively small area.
  • the first protruding portion 297 a may be configured to have a width W 1 wider than a width W 2 of the second protruding portion 297 b.
  • the first protruding portion 297 a may be larger than the second protruding portion 297 b in view of an area.
  • the core area of the front portion 350 f of the d-axis d may be smaller than the core area of the rear portion 350 r of the d-axis d.
  • the first protruding portion 297 a may include a larger number of unit plane figures 410 than the second protruding portion 297 b.
  • the second permanent magnet insertion portion 310 may include a second permanent magnet accommodation space 312 in which the second permanent magnet 452 is accommodated, a second flux barrier 314 extending from one side of the second permanent magnet accommodation space 312 , and the second expansion slot 315 expanded toward the d-axis d.
  • the second expansion slot 315 may have, for example, a rectangular shape which is long in length along a lengthwise direction of the second permanent magnet 452 .
  • the second expansion slot 315 may include, for example, an outer side 315 So disposed in parallel with the outer side 312 So of the second permanent magnet insertion portion 310 , and both sides 315 Ss extending from both end portions of the outer side 315 So to be connected to the outer side 312 So of the second permanent magnet insertion portion 310 .
  • the rotor 250 may rotate in a preset direction (counterclockwise in the drawing) centering on the rotation shaft 260 , in response to an interaction between a magnetic field formed by the stator coil 171 and a magnetic field of the permanent magnets 450 .
  • MPF formed at the front portion 350 f of the d-axis d and MPF formed at the rear portion 350 r of the d-axis d may be asymmetrical with each other due to the slot 400 , with respect to the d-axis d that is a center of the magnetic pole of the rotor 250 .
  • the MPF formed at the front portion 350 f of the d-axis d which acts in a direction of suppressing the rotation of the rotor 250 may become smaller than the MPF formed at the rear portion 350 r of the d-axis d which acts in a direction of facilitating the rotation of the rotor 250 . Accordingly, vibration and noise occurred in the rotor 250 can be suppressed.
  • the slot 400 may be formed through the rotor 250 such that the core area of the front portion 350 f of the d-axis d is smaller than the core area of the rear portion 350 r of the d-axis d. Accordingly, the reduction of the core area of the rear portion 350 r of the d-axis d can be suppressed, resulting in preventing a decrease in inertia of the rotor 250 . An occurrence of vibration during low speed rotation of the rotor 250 can be prevented as well. In addition, an input may be reduced during the low speed rotation of the rotor 250 , thereby improving operation efficiency.
  • FIG. 9 is a horizontal sectional view of an electric motor in accordance with another implementation
  • FIG. 10 is an enlarged view of a slot region of FIG. 9
  • an electric motor 200 a may include a stator 210 and a rotor 250 .
  • the stator 210 may include a stator core 220 and a stator coil 230 wound around the stator core 220 .
  • the rotor 250 may include a rotation shaft 260 , a rotor core 270 , and a plurality of permanent magnets 450 coupled to the rotor core 270 in an axial direction.
  • the rotor 250 may have different magnetic poles alternately formed in a circumferential direction.
  • the rotor 250 may be provided with two permanent magnets 450 for each magnetic pole.
  • Each of the permanent magnets 450 may include a first permanent magnet 451 and a second permanent magnet 452 arranged in a “V” shape with respect to a d-axis d.
  • the rotor core 270 may include a permanent magnet insertion portion 280 formed therethrough in the axial direction so that the permanent magnet 450 can be inserted, and a slot 400 a formed therethrough in the axial direction such that a core area of a front portion 350 f of the d-axis d is smaller than a core area of a rear portion 350 r of the d-axis din a rotating direction of the rotor 250 when an outer core part 350 of the permanent magnet insertion portion 280 is divided based on the d-axis d.
  • the permanent magnet insertion portion 280 may include a first permanent magnet insertion portion 290 into which the first permanent magnet 451 is inserted, and a second permanent magnet insertion portion 310 into which the second permanent magnet 452 is inserted.
  • the first permanent magnet insertion portion 290 may include a first permanent magnet accommodation space 292 in which the first permanent magnet 451 is accommodated, a first flux barrier 294 extending from one side of the first permanent magnet accommodation space 292 , and a first expansion slot 295 expanded toward the d-axis d.
  • the second permanent magnet insertion portion 310 may include a second permanent magnet accommodation space 312 in which the second permanent magnet 452 is accommodated, a second flux barrier 314 extending from one side of the second permanent magnet accommodation space 312 , and a second expansion slot 315 expanded toward the d-axis d.
  • the slot 400 a may include, for example, a first side 400 a S 1 arranged at the outside of the outer side 292 So of the first permanent magnet insertion portion 290 to be in parallel with the outer side 292 So, and a second side 400 a S 2 extending from the first side 400 a S 1 to be in parallel with the outer side 312 So of the second permanent magnet insertion portion 310 .
  • the slot 400 a may include, for example, a third side 400 a S 3 extending from an end portion of the second side 400 a S 2 to be in parallel with the first side 400 a S 1 , and a connection section 400 a A connecting the first side 400 a S 1 and the third side 400 a S 3 .
  • connection section 400 a A may be implemented in an arcuate shape to maintain a preset distance from the outer circumference of the rotor core 270 .
  • the slot 400 a may include a plurality of unit plane figures 410 having a relatively small area.
  • the unit plane FIG. 410 may be implemented, for example, as a parallelogram having two sides arranged in parallel with the outer side 292 So of the first permanent magnet insertion portion 290 , and two other sides arranged in parallel with the outer side 312 So of the second permanent magnet insertion portion 310 .
  • the slot 400 a may have a fourth side (not shown) linearly connecting the first side 400 a S 1 and the third side 400 a S 3 .
  • the fourth side (not shown) may be configured to have the connection section 400 a A formed in the arcuate shape to maintain the same distance from the outer circumference of the rotor core 270 .
  • the rotor 250 may rotate in a preset direction (counterclockwise in the drawing) centering on the rotation shaft 260 , in response to an interaction between a magnetic field formed by the stator coil 171 and a magnetic field of the permanent magnets 450 .
  • MPF formed at the front portion 350 f of the d-axis d and MPF formed at the rear portion 350 r of the d-axis d may be asymmetrical with each other due to the slot 400 a , with respect to the d-axis d that is a center of the magnetic pole of the rotor 250 . This may result in suppressing an occurrence of vibration and noise of the rotor 250 .
  • the slot 400 a may be formed through the rotor 250 such that the core area of the front portion 350 f of the d-axis d is smaller than the core area of the rear portion 350 r of the d-axis d. Accordingly, the reduction of the core area of the rear portion 350 r of the d-axis d can be suppressed, resulting in preventing a decrease in inertia of the rotor 250 . An occurrence of vibration during a low speed rotation of the rotor 250 can be prevented as well. In addition, an input may be reduced during the low speed rotation of the rotor 250 , thereby improving operation efficiency.
  • FIG. 11 is a horizontal sectional view of an electric motor in accordance with another implementation
  • FIG. 12 is an enlarged view of a slot region of FIG. 11
  • An electric motor 200 b according to this implementation may include a stator 210 and a rotor 250 as illustrated in FIGS. 11 and 12 .
  • the stator 210 may include a stator core 220 having a plurality of slots 226 and teeth 228 , and a stator coil 230 wound around the stator core 220 .
  • the rotor 250 may include a rotation shaft 260 , a rotor core 270 , and a plurality of permanent magnets 450 .
  • the rotor 250 may have different magnetic poles (N pole and S pole) alternately formed in a circumferential direction.
  • the rotor 250 may include a first permanent magnet 451 and a second permanent magnet 452 for each pole.
  • the first permanent magnet 451 and the second permanent magnet 452 may be arranged to form a preset interior angle (e.g., 108 degrees).
  • the rotor core 270 may include a permanent magnet insertion portion 280 formed therethrough in an axial direction so that the permanent magnet 450 can be inserted, and a slot 400 b formed therethrough in the axial direction such that a core area of a front portion 350 f of a d-axis d is smaller than a core area of a rear portion 350 r of the d-axis din a rotating direction of the rotor 250 when an outer core part 350 of the permanent magnet insertion portion 280 is divided based on the d-axis d.
  • the first permanent magnet insertion portion 290 may include a first permanent magnet accommodation space 292 in which the first permanent magnet 451 is accommodated, and a first flux barrier 294 extending from one side of the first permanent magnet accommodation space 292 .
  • the second permanent magnet insertion portion 310 may include a second permanent magnet accommodation space 312 in which the second permanent magnet 452 is accommodated, and a second flux barrier 314 extending from one side of the second permanent magnet accommodation space 312 .
  • the slot 400 b may include, for example, a front slot 400 b 1 disposed in the front portion 350 f of the d-axis d and a rear slot 400 b 2 disposed in the rear portion 350 r of the d-axis d.
  • the front slot 400 b 1 may include, for example, a first front slot 400 b 11 formed at the front of the d-axis d, and a second front slot 400 b 12 formed at an outer end region of the first permanent magnet 451 .
  • the second front slot 400 b 12 may be referred to as a first slot
  • the rear slot 400 b 2 may be referred to as a second slot
  • the first front slot 400 b 11 may be referred to as a third slot defined between the second front slot 400 b 12 and the d-axis.
  • Each of the front slot 400 b 1 and the rear slot 400 b 2 may include a plurality of unit plane figures 410 having a relatively small area.
  • the second front slot 400 b 12 may be formed through the rotor core 270 , for example, with being spaced a preset distance apart from a boundary region between the first permanent magnet accommodation space 292 and the first flux barrier 294 .
  • the rear slot 400 b 2 may be formed through the rotor core 270 , for example, with being spaced apart from a boundary region between the second permanent magnet accommodating space 312 and the second flux barrier 314 .
  • the second front slot 400 b 12 and the rear slot 400 b 2 may be formed symmetrically with each other with respect to the d-axis d, for example.
  • the first front slot 400 b 11 and the second front slot 400 b 12 may be formed through the d-axis front outer part ⁇ circle around (1) ⁇ .
  • the rear slot 400 b 2 may be formed through the d-axis rear outer part ⁇ circle around (4) ⁇ .
  • the unit plane FIG. 410 may be implemented, for example, as a parallelogram having two sides arranged in parallel with the outer side 292 So of the first permanent magnet insertion portion 290 , and two other sides arranged in parallel with the outer side 312 So of the second permanent magnet insertion portion 310 .
  • outlines of the first front slot 400 b 11 , the second front slot 400 b 12 , and the rear slot 400 b 2 may be implemented in a linear or curved shape, for example. More specifically, outlines of the first front slot 400 b 11 , the second front slot 400 b 12 , and the rear slot 400 b 2 may be formed by connecting the outlines of the adjacent unit plane figures 410 . More specifically, the outlines of the first front slot 400 b 11 , the second front slot 400 b 12 , and the rear slot 400 b 2 may define a step shape when enlarged at a large magnification.
  • the rotor 250 may rotate in a preset direction centering on the rotation shaft 260 , in response to an interaction between a magnetic field formed by the stator coil 171 and a magnetic field of the permanent magnets 450 .
  • MPF formed at the front portion 350 f of the d-axis d and MPF formed at the rear portion 350 r of the d-axis d may be asymmetrical with each other due to the slot 400 b , with respect to the d-axis d that is a center of the magnetic pole of the rotor 250 . This may result in suppressing an occurrence of vibration and noise of the rotor 250 .
  • the slot 400 b may be formed through the rotor 250 such that the core area of the front portion 350 f of the d-axis d is smaller than the core area of the rear portion 350 r of the d-axis d. Accordingly, the reduction of the core area of the rear portion 350 r of the d-axis d can be suppressed, resulting in preventing a decrease in inertia of the rotor 250 . An occurrence of vibration during low speed rotation of the rotor 250 can be prevented as well. In addition, an input may be reduced during the low speed rotation of the rotor 250 , thereby improving operation efficiency.
  • FIG. 13 is a horizontal sectional view of an electric motor in accordance with another implementation
  • FIG. 14 is an enlarged view of a slot region of FIG. 13
  • an electric motor 200 c may include a stator 210 and a rotor 250 .
  • the stator 210 may include a stator core 220 and a stator coil 230 wound around the stator core 220 .
  • the rotor 250 may include a rotation shaft 260 , a rotor core 270 , and a plurality of permanent magnets 450 .
  • the rotor 250 may have different magnetic poles (N pole and S pole) alternately formed in a circumferential direction.
  • Each of the permanent magnets 450 may include a first permanent magnet 451 and a second permanent magnet 452 for each pole.
  • the rotor core 270 may include a permanent magnet insertion portion 280 formed therethrough in an axial direction so that the permanent magnet 450 can be inserted, and a slot 400 c formed therethrough in the axial direction such that a core area of a front portion 350 f of a d-axis d is smaller than a core area of a rear portion 350 r of the d-axis din the rotating direction of the rotor 250 when an outer core part 350 of the permanent magnet insertion portion 280 is divided based on the d-axis d.
  • the permanent magnet insertion portion 280 may include a first permanent magnet insertion portion 290 and a second permanent magnet insertion portion 310 .
  • the first permanent magnet insertion portion 290 may include a first permanent magnet accommodation space 292 in which the first permanent magnet 451 is accommodated, a first flux barrier 294 extending from one side of the first permanent magnet accommodation space 292 , and a first expansion slot 295 expanded toward the d-axis d.
  • the second permanent magnet insertion portion 310 may include a second permanent magnet accommodation space 312 in which the second permanent magnet 452 is accommodated, a second flux barrier 314 extending from one side of the second permanent magnet accommodation space 312 , and a second expansion slot 315 expanded toward the d-axis d.
  • the slot 400 c may be formed, for example, through the d-axis front outer part ⁇ circle around (1) ⁇ .
  • the slot 400 c may include, for example, a first side 400 cS 1 arranged at the outside of the outer side 292 So of the first permanent magnet insertion portion 290 to be in parallel with the outer side 292 So, and a second side 400 c S 2 extending from the first side 400 c S 1 to be in parallel with the outer side 312 So of the second permanent magnet insertion portion 310 .
  • the slot 400 c may include, for example, a third side 400 c S 3 arranged at the outside of the first side 400 c S 1 in parallel, and a fourth side 400 c S 4 arranged at the outside of the second side 400 c S 2 in parallel.
  • a distance between the fourth side 400 c S 4 and the second side 400 c S 2 may be larger than a distance between the first side 400 c S 1 and the third side 400 c S 3 .
  • an outer end portion of the first side 400 c S 1 and an outer end portion of the third side 400 c S 3 may be connected by, for example, a straight line 400 c S 5 .
  • An outer end portion of the second side 400 c S 2 and an outer end portion of the fourth side 400 c S 4 may be connected by, for example, a straight line 400 c S 6 .
  • the slot 400 c may be provided with a plurality of rectangular sections.
  • the plurality of rectangular sections of the slot 400 c may include a plurality of unit plane figures 410 having a relatively small area.
  • the unit plane FIG. 410 may be implemented, for example, as a parallelogram having two sides arranged in parallel with the outer side 292 So of the first permanent magnet insertion portion 290 , and two other sides arranged in parallel with the outer side 312 So of the second permanent magnet insertion portion 310 .
  • the rotor 250 may rotate in a preset direction centering on the rotation shaft 260 , in response to an interaction between a magnetic field formed by the stator coil 171 and a magnetic field of the permanent magnets 450 .
  • MPF formed at the front portion 350 f of the d-axis d and MPF formed at the rear portion 350 r of the d-axis d may be asymmetrical with each other due to the slot 400 c , with respect to the d-axis d that is a center of the magnetic pole of the rotor 250 . This may result in suppressing an occurrence of vibration and noise of the rotor 250 .
  • the slot 400 c may be formed through the rotor 250 such that the core area of the front portion 350 f of the d-axis d is smaller than the core area of the rear portion 350 r of the d-axis d. Accordingly, the reduction of the core area of the rear portion 350 r of the d-axis d can be suppressed, resulting in preventing a decrease in inertia of the rotor 250 . An occurrence of vibration during low speed rotation of the rotor 250 can be prevented as well. In addition, an input may be reduced during the low speed rotation of the rotor 250 , thereby improving operation efficiency.
  • FIG. 15 is a horizontal sectional view of an electric motor in accordance with another implementation
  • FIG. 16 is an enlarged view of a slot region of FIG. 15
  • an electric motor 200 d may include a stator 210 and a rotor 250 .
  • the rotor 250 may include a rotation shaft 260 , a rotor core 270 , and a plurality of permanent magnets 450 .
  • the rotor 250 may have different magnetic poles (N pole and S pole) alternately formed in the circumferential direction.
  • the rotor 250 may include a first permanent magnet 451 and a second permanent magnet 452 for each pole.
  • the rotor core 270 may include a permanent magnet insertion portion 280 formed therethrough in an axial direction so that the permanent magnet 450 can be inserted, and a slot 400 d formed therethrough in the axial direction such that a core area of a front portion 350 f of a d-axis d is smaller than a core area of a rear portion 350 r of the d-axis din a rotating direction of the rotor 250 when an outer core part 350 of the permanent magnet insertion portion 280 is divided based on the d-axis d.
  • the first permanent magnet insertion portion 290 may include a first permanent magnet accommodation space 292 in which the first permanent magnet 451 is accommodated, and a first flux barrier 294 extending from one side of the first permanent magnet accommodation space 292 .
  • the second permanent magnet insertion portion 310 may include a second permanent magnet accommodation space 312 in which the second permanent magnet 452 is accommodated, and a second flux barrier 314 extending from one side of the second permanent magnet accommodation space 312 .
  • the slot 400 d may include, for example, a front slot 400 d 1 disposed in the front portion 350 f of the d-axis d and a rear slot 400 d 2 disposed in the rear portion 350 r of the d-axis d.
  • the slot 400 d 1 may be formed, for example, through the d-axis front outer part ⁇ circle around (1) ⁇ .
  • the rear slot 400 d 2 may be formed, for example, through the d-axis rear outer part ⁇ circle around (4) ⁇ .
  • the area of the front slot 400 d 1 may be larger than the area of the rear slot 400 d 2 .
  • the core area of the front portion 350 f of the d-axis d may be smaller than the core area of the rear portion 350 r of the d-axis d.
  • the front slot 400 d 1 may include, for example, a first side 400 d 1 S 1 arranged in parallel with the outer side 292 So of the first permanent magnet insertion portion 290 , and a second side 400 d 1 S 2 extending from the first side 400 d 1 S 1 to be in parallel with the outer side 312 So of the second permanent magnet insertion portion 310 .
  • the front slot 400 d 1 may further include, for example, a third side 400 d 1 S 3 extending from an end portion of the second side 400 d 1 S 2 to be in parallel with the first side 400 a S 1 , an arcuate section 400 d 1 A extending from an end portion of the first side 400 d 1 S 1 to be in parallel with an outer circumference of the rotor core 270 , and a connection section 400 d 1 S 4 connecting the arcuate section 400 d 1 A and the third side 400 d 1 S 3 .
  • the outer circumference of the rotor core 270 and the arcuate section 400 d 1 A may be configured to maintain the same distance W therebetween.
  • the rear slot 400 d 2 may include, for example, a first side 400 d 2 S 1 arranged in parallel with the outer side 292 So of the first permanent magnet insertion portion 290 , and a second side 400 d 2 S 2 extending from the first side 400 d 2 S 1 to be in parallel with the outer side 312 So of the second permanent magnet insertion portion 310 .
  • the rear slot 400 d 2 may include, for example, a third side 400 d 2 S 3 extending from an end portion of the second side 400 d 2 S 2 to be in parallel with the first side 400 d 2 S 1 , and a fourth side 400 d 2 S 4 extending from the third side 400 d 2 S 3 to be in parallel with the first side 400 d 2 S 1 .
  • the first side 400 d 2 S 1 and the third side 400 d 2 S 3 of the rear slot 400 d 2 may be connected, for example, by a straight line 400 d 2 S 5 .
  • the second side 400 d 2 S 2 and the fourth side 400 d 2 S 4 of the rear slot 400 d 2 may be connected, for example, by a straight line 400 d 2 S 6 .
  • Each of the front slot 400 d 1 and the rear slot 400 d 2 may include a plurality of unit plane figures 410 having a relatively small area.
  • the unit plane FIG. 410 may be implemented, for example, as a parallelogram having two sides arranged in parallel with the outer side 292 So of the first permanent magnet insertion portion 290 , and two other sides arranged in parallel with the outer side 312 So of the second permanent magnet insertion portion 310 .
  • the rotor 250 may rotate in a preset direction centering on the rotation shaft 260 , in response to an interaction between a magnetic field formed by the stator coil 171 and a magnetic field of the permanent magnets 450 .
  • MPF formed at the front portion 350 f of the d-axis d and MPF formed at the rear portion 350 r of the d-axis d may be asymmetrical with each other due to the slot 400 d , with respect to the d-axis d that is a center of the magnetic pole of the rotor 250 . This may result in suppressing an occurrence of vibration and noise of the rotor 250 .
  • the slot 400 d may be formed through the rotor 250 such that the core area of the front portion 350 f of the d-axis d is smaller than the core area of the rear portion 350 r of the d-axis d. Accordingly, the reduction of the core area of the rear portion 350 r of the d-axis d can be suppressed, resulting in preventing a decrease in inertia of the rotor 250 . An occurrence of vibration during low speed rotation of the rotor 250 can be prevented as well. In addition, an input may be reduced during the low speed rotation of the rotor 250 , thereby improving operation efficiency.
  • FIG. 17 is a horizontal sectional view of an electric motor in accordance with another implementation
  • FIG. 18 is an enlarged view of a slot region of FIG. 17
  • an electric motor 200 d may include a stator 210 and a rotor 250 .
  • the rotor 250 may include a rotation shaft 260 , a rotor core 270 , and a plurality of permanent magnets 450 .
  • the rotor 250 may have different magnetic poles (N pole and S pole) alternately formed in a circumferential direction.
  • the rotor 250 may include a first permanent magnet 451 and a second permanent magnet 452 for each pole.
  • the rotor core 270 may include a permanent magnet insertion portion 280 formed therethrough in an axial direction so that the permanent magnet 450 can be inserted, and a slot 400 d ′ formed therethrough in the axial direction such that a core area of a front portion 350 f of a d-axis d is smaller than a core area of a rear portion 350 r of the d-axis din a rotating direction of the rotor 250 when an outer core part 350 of the permanent magnet insertion portion 280 is divided based on the d-axis d.
  • the first permanent magnet insertion portion 290 may include a first permanent magnet accommodation space 292 in which the first permanent magnet 451 is accommodated, and a first flux barrier 294 extending from one side of the first permanent magnet accommodation space 292 .
  • the second permanent magnet insertion portion 310 may include a second permanent magnet accommodation space 312 in which the second permanent magnet 452 is accommodated, and a second flux barrier 314 extending from one side of the second permanent magnet accommodation space 312 .
  • the slot 400 d ′ may include, for example, a front slot 400 d 1 disposed in the front portion 350 f of the d-axis d, a rear slot 400 d 2 disposed in the rear portion 350 r of the d-axis d, and a central slot 400 d 3 formed over the front and rear sides of the d-axis d.
  • the front slot 400 d 1 may be formed, for example, through the d-axis front outer part ⁇ circle around (4) ⁇ .
  • the rear slot 400 d 2 may be formed, for example, through the d-axis rear outer part ⁇ circle around (4) ⁇ .
  • the central slot 400 d 3 may be formed all over, for example, the d-axis front outer part ⁇ circle around (1) ⁇ , the d-axis front inner part ⁇ circle around (2) ⁇ , the d-axis rear inner part ⁇ circle around (3) ⁇ , and the d-axis rear outer part ⁇ circle around (4) ⁇ .
  • This implementation illustrates that the central slot 400 d 3 is formed over the d-axis front outer part ⁇ circle around (1) ⁇ , the d-axis front inner part ⁇ circle around (2) ⁇ , the d-axis rear inner part ⁇ circle around (3) ⁇ , and the d-axis rear outer part ⁇ circle around (4) ⁇ .
  • this implementation is merely illustrative and the present disclosure may not be limited to this.
  • the central slot 400 d 3 may alternatively be formed over, for example, the d-axis front inner part ⁇ circle around (2) ⁇ and the d-axis rear inner part ⁇ circle around (3) ⁇ .
  • the front slot 400 d 1 may be larger than the rear slot 400 d 2 in view of an area.
  • the core area of the front portion 350 f of the d-axis d may be smaller than the core area of the rear portion 350 r of the d-axis d.
  • the front slot 400 d 1 may include, for example, a first side 400 d 1 S 1 arranged in parallel with the outer side 292 So of the first permanent magnet insertion portion 290 , and a second side 400 d 1 S 2 extending from the first side 400 d 1 S 1 to be in parallel with the outer side 312 So of the second permanent magnet insertion portion 310 .
  • the front slot 400 d 1 may further include, for example, a third side 400 d 1 S 3 extending from an end portion of the second side 400 d 1 S 2 to be in parallel with the first side 400 a S 1 , an arcuate section 400 d 1 A extending from an end portion of the first side 400 d 1 S 1 to be in parallel with an outer circumference of the rotor core 270 , and a connection section 400 d 1 S 4 connecting the arcuate section 400 d 1 A and the third side 400 d 1 S 3 .
  • the outer circumference of the rotor core 270 and the arcuate section 400 d 1 A may be configured to maintain the same distance W therebetween.
  • the rear slot 400 d 2 may include, for example, a first side 400 d 2 S 1 arranged in parallel with the outer side 292 So of the first permanent magnet insertion portion 290 , and a second side 400 d 2 S 2 extending from the first side 400 d 2 S 1 to be in parallel with the outer side 312 So of the second permanent magnet insertion portion 310 .
  • the rear slot 400 d 2 may include, for example, a third side 400 d 2 S 3 extending from an end portion of the second side 400 d 2 S 2 to be in parallel with the first side 400 d 2 S 1 , and a fourth side 400 d 2 S 4 extending from the third side 400 d 2 S 3 to be in parallel with the first side 400 d 2 S 1 .
  • the central slot 400 d 3 may include, for example, a first side 400 d 3 S 1 disposed in parallel with the outer side 292 So of the first permanent magnet insertion portion 290 , a second side 400 d 3 S 2 extending from one end portion of the first side 400 d 3 S 1 to be in parallel with the outer side 312 So of the second permanent magnet insertion portion 310 , a third side 400 d 3 S 3 extending from another end portion of the first side 400 d 3 S 1 to be in parallel with the second side 400 d 3 S 2 , and a fourth side 400 d 3 S 4 extending from another end portion of the second side 400 d 3 S 2 to be in parallel with the first side 400 d 3 S 1 .
  • the front slot 400 d 1 , the rear slot 400 d 2 , and the central slot 400 d 3 may be configured such that a total area of the slot disposed in the d-axis rear inner part ⁇ circle around (3) ⁇ is equal to or larger than a total area of the slot disposed in the d-axis rear outer part ⁇ circle around (4) ⁇ .
  • a total area of the slot disposed in the d-axis front inner part ⁇ circle around (2) ⁇ may be equal to or larger than a total area of the slot disposed in the d-axis rear inner part ⁇ circle around (3) ⁇ .
  • a total area of the slot disposed in the d-axis front outer part ⁇ circle around (1) ⁇ may be equal to or larger than a total area of the slot disposed in the d-axis front inner part ⁇ circle around (2) ⁇ .
  • each of the front slot 400 d 1 , the rear slot 400 d 2 , and the central slot 400 d 3 may include a plurality of unit plane figures 410 having a relatively small area.
  • the unit plane FIG. 410 may be implemented, for example, as a parallelogram having two sides arranged in parallel with the outer side 292 So of the first permanent magnet insertion portion 290 , and two other sides arranged in parallel with the outer side 312 So of the second permanent magnet insertion portion 310 .
  • the rotor 250 may rotate in a preset direction centering on the rotation shaft 260 , in response to an interaction between a magnetic field formed by the stator coil 171 and a magnetic field of the permanent magnets 450 .
  • MPF formed at the front portion 350 f of the d-axis d and MPF formed at the rear portion 350 r of the d-axis d may be asymmetrical with each other due to the slot 400 d ′, with respect to the d-axis d that is a center of the magnetic pole of the rotor 250 . This may result in suppressing an occurrence of vibration and noise of the rotor 250 .
  • the slot 400 d ′ may be formed through the rotor 250 such that the core area of the front portion 350 f of the d-axis d is smaller than the core area of the rear portion 350 r of the d-axis d. Accordingly, the reduction of the core area of the rear portion 350 r of the d-axis d can be suppressed, resulting in preventing a decrease in inertia of the rotor 250 . An occurrence of vibration during a low speed rotation of the rotor 250 can be prevented as well. In addition, an input may be reduced during the low speed rotation of the rotor 250 , thereby improving operation efficiency.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Permanent Field Magnets Of Synchronous Machinery (AREA)
  • Iron Core Of Rotating Electric Machines (AREA)
US17/060,705 2020-01-22 2020-10-01 Electric motor and compressor having the same Active 2041-05-11 US11604014B2 (en)

Applications Claiming Priority (2)

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KR10-2020-0008856 2020-01-22
KR1020200008856A KR102351792B1 (ko) 2020-01-22 2020-01-22 전동기 및 이를 구비한 압축기

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US11604014B2 true US11604014B2 (en) 2023-03-14

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KR (1) KR102351792B1 (de)
CN (1) CN212935603U (de)
DE (1) DE102020214502A1 (de)

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JP1665115S (de) * 2020-02-27 2020-08-03
JP1665117S (de) * 2020-02-27 2020-08-03

Citations (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09131009A (ja) 1995-10-31 1997-05-16 Mitsubishi Electric Corp 永久磁石回転子
JPH10285851A (ja) 1997-04-07 1998-10-23 Mitsubishi Electric Corp 永久磁石型モータ
US6147428A (en) * 1997-04-14 2000-11-14 Sanyo Electric Co., Ltd. Rotor of electric motor
US7151335B2 (en) * 2004-03-10 2006-12-19 Hitachi, Ltd. Permanent magnet rotating electric machine and electric car using the same
JP3906883B2 (ja) * 1997-10-29 2007-04-18 株式会社富士通ゼネラル 永久磁石電動機
KR100711363B1 (ko) 2003-09-19 2007-04-27 도시바 캐리어 가부시키 가이샤 영구자석 전동기
JP2008199790A (ja) 2007-02-13 2008-08-28 Daikin Ind Ltd 永久磁石埋め込み型ロータ
JP2009050153A (ja) 2007-08-16 2009-03-05 Ford Global Technologies Llc 永久磁石式回転電機
US8018109B2 (en) * 2008-11-11 2011-09-13 Ford Global Technologies, Llc Permanent magnet machine with offset pole spacing
WO2012141085A1 (ja) * 2011-04-15 2012-10-18 三菱重工業株式会社 電動モータおよびそれを用いた電動圧縮機
KR20130062872A (ko) 2011-12-05 2013-06-13 삼성전자주식회사 브러시리스 모터
JP2014226008A (ja) 2013-05-17 2014-12-04 本田技研工業株式会社 回転電機のロータ
US20150069874A1 (en) * 2012-04-10 2015-03-12 Honda Motor Co., Ltd. Rotating electric machine rotor
KR20150059974A (ko) 2013-11-25 2015-06-03 삼성전자주식회사 전동기
CN208241436U (zh) 2018-06-20 2018-12-14 广东美芝制冷设备有限公司 转子铁芯、永磁电机及压缩机

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11187597A (ja) 1997-12-19 1999-07-09 Matsushita Electric Ind Co Ltd 永久磁石埋め込みロータ

Patent Citations (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09131009A (ja) 1995-10-31 1997-05-16 Mitsubishi Electric Corp 永久磁石回転子
JPH10285851A (ja) 1997-04-07 1998-10-23 Mitsubishi Electric Corp 永久磁石型モータ
US6147428A (en) * 1997-04-14 2000-11-14 Sanyo Electric Co., Ltd. Rotor of electric motor
JP3906883B2 (ja) * 1997-10-29 2007-04-18 株式会社富士通ゼネラル 永久磁石電動機
KR100711363B1 (ko) 2003-09-19 2007-04-27 도시바 캐리어 가부시키 가이샤 영구자석 전동기
US7151335B2 (en) * 2004-03-10 2006-12-19 Hitachi, Ltd. Permanent magnet rotating electric machine and electric car using the same
JP2008199790A (ja) 2007-02-13 2008-08-28 Daikin Ind Ltd 永久磁石埋め込み型ロータ
JP2009050153A (ja) 2007-08-16 2009-03-05 Ford Global Technologies Llc 永久磁石式回転電機
US8018109B2 (en) * 2008-11-11 2011-09-13 Ford Global Technologies, Llc Permanent magnet machine with offset pole spacing
WO2012141085A1 (ja) * 2011-04-15 2012-10-18 三菱重工業株式会社 電動モータおよびそれを用いた電動圧縮機
KR20130062872A (ko) 2011-12-05 2013-06-13 삼성전자주식회사 브러시리스 모터
US20150069874A1 (en) * 2012-04-10 2015-03-12 Honda Motor Co., Ltd. Rotating electric machine rotor
JP2014226008A (ja) 2013-05-17 2014-12-04 本田技研工業株式会社 回転電機のロータ
KR20150059974A (ko) 2013-11-25 2015-06-03 삼성전자주식회사 전동기
CN208241436U (zh) 2018-06-20 2018-12-14 广东美芝制冷设备有限公司 转子铁芯、永磁电机及压缩机

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
KR Office Action in Korean Appln. No. 10-2020-0008856, dated Jun. 24, 2021, 10 pages (with English translation).
Notice of Allowance in Korean Appln. No. 10-2020-0008856, dated Jan. 3, 2022, 7 pages (with English translation).

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US20210222922A1 (en) 2021-07-22
KR102351792B1 (ko) 2022-01-17
KR20210094953A (ko) 2021-07-30
CN212935603U (zh) 2021-04-09
DE102020214502A1 (de) 2021-07-22

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